Call it the Slumdog syndrome, or the King's Speech complex. A massive, unexpected hit movie comes along, outside the precision-engineered channels of the studio system. Obviously the shop-window people – the actors, the director – get a lot out of it. But behind the scenes, the transformation can be even more radical; the producer will suddenly become the most feted figure in the industry. Slumdog Millionaire turned Christian Colson into a major industry player. Iain Canning and Emile Sherman became overnight heavyweights after The King's Speech. Now, a little something called The Inbetweeners Movie, and its £41m box-office take, has instantly turned its Scottish producer, Christopher Young, into the man everyone wants to do business with.

"It's been like night and day," he says. "I can trace it to a single point: the moment our opening day's figures got out. We did £2.5m on the Wednesday preview, so that became a story by the Thursday afternoon. That's when the emails started coming in. Then we did £13.2m for our first weekend. Suddenly people who never gave me the time of day were saying, 'Why aren't we having a conversation? Where have you been, Chris?'"

The truth is that Young has been here all along. Now 51, he has clocked up more than 20 years as a producer, mostly in Scotland, valiantly plugging away since the late 1980s. If Young has been known for anything in the last two decades, it's been for unquenchable enthusiasm in the service of projects that, more often than not, didn't necessarily merit it.

He reached his low point in 2007 when, with nothing else happening, he sunk his money and energy into a Gaelic-language children's film called Seachd: The Inaccessible Pinnacle, to be shot on Skye. It was an interesting idea, for sure, but about as uncommercial as you can get. "Frankly, I was on my uppers after that. I'd spent a long time making it, it was very low budget and I found it very hard to sell it. I definitely had reached a dead end."

What saved him was a phone call from the Channel 4 drama department, asking him to work on a teen sitcom that at that point was called Baggy Trousers. Young says he didn't really want to do it, but had little option. "It felt like I was letting go of some kind of dream. Right from the beginning, I had been mad about movies. My heroes were Fellini, Visconti, the Japanese directors. A lot of my failures as a producer were to do with being attached to that kind of difficult, obscure film. I had run a film company for 20 years, and ultimately hadn't managed to succeed with what I was trying to do. That was very hard. I thought: does doing a TV sitcom mean it is over with film?"

Five years later, Young is sitting on top of one of British cinema's biggest ever hits, and still sounds stunned as to how it happened. "I was very buoyed by the success of the TV show, but the film has shaken me. I'm not used to seeing doubledecker buses with my signage on it. Nor on motorway advertising billboards. From the moment the campaign started, it was very exciting; I've never played the game on that scale before. I must admit, I absolutely loved it.

"Most doors have been shut to me for years; I struggled to get calls returned. There are people who have been absolute shits for the last 20 years who have suddenly become embarrassingly friendly and obsequious. But there are also people who have been nice, who, like me, have been struggling away, and have been supportive of me in the past, and I'm very grateful to them. But I never expected to be in this position with what I signed up for with E4 five years ago. It's the irony of ironies: doing a sitcom has made me discover how to make a successful film."